I like reading the Perl Weekly Challenge even if I rarely participate.
It struck me that task 1 of Week 20 asked "to accept a string from command line and split it on change of character" - but every solution that I read in the recap looked for runs of the same character instead of the literal interpretation of the challenge.
Then I found, it was a dead end for me...
$ perl -E 'say join " ",split /(.)(?!\1)/,scalar '
ABBCDEEF
A B B C D E E …